Another way of saying it is that we can learn more from the shape of the yield curve and credit spreads than by looking at backward - looking estimates of asset class returns. (alephblog.com)
The data sources for monthly asset class returns are listed below. (portfoliovisualizer.com)
Then, as debts become unsustainable, there are crashes where the previously favored asset class returns to reasonable pricing or less. (alephblog.com)